Conventionally, a gas mixture supplying apparatus for mixing and supplying gases, so-called a gas box or the like, is generally employed when a gas mixture including different kinds of gases is supplied as a processing gas into a region where the gas mixture is used such as a processing chamber of a semiconductor manufacturing apparatus, e.g., when an etching gas is supplied into a processing chamber of a plasma etching apparatus.
The gas mixture supplying apparatus is configured to mix and supply plural gases through a plurality of gas supply lines connected to one common pipeline (manifold) and then to supply the mixture of the gases into the region where the mixture of gases is used through a gas mixture supply line via a gas outlet of the common pipeline.
A gas supplied by using the gas mixture supplying apparatus includes a gas in the gaseous state at a normal temperature and pressure, which is supplied from a gas supply unit in the gaseous state, (hereinafter, referred to as “typical gas”); and a gas vaporized by heating a liquid source material supplied from a liquid source material supply unit by a vaporizing unit (hereinafter, referred to as “liquid source gas”). To supply such liquid source gas, there is known a method of supplying a liquid source gas having a relatively low vapor pressure from a position closer to the processing chamber (see, e.g., Japanese Patent Application Publication No. 1996-88191 and its corresponding U.S. Pat. No. 6,464,782).
When the etching gas is supplied into the processing chamber of the plasma etching apparatus or the like by using the gas mixture supplying apparatus as described above, a filter is provided in the common pipeline (manifold) or the gas mixture supply line to remove particles present in the gas mixture after the typical gas and the liquid source gas are mixed. Since, however, this filter has low conductance, a pressure of the gas mixture may be increased in this filter, raising likelihood that the liquid source gas may be condensed. For this reason, the common pipeline (manifold), the gas mixture supply line and so forth are conventionally heated to a high temperature by a heater, thus preventing the condensation of the liquid source gas.
In the conventional technology as stated above, however, since the common pipeline (manifold), the gas mixture supply line and so forth need to be heated to the high temperature by the heater to prevent the condensation of the liquid source gas, there has been a problem that the power consumption is increased due to the heating by the heater may be increased.